1. Field of the Invention
The present invention relates to an exercise therapy device capable of recovering the exercise function of and maintaining the physical strength of a physically handicapped person or an aged person by auxiliarily and passively assisting a rotational movement of each pedal when the person undergoes an exercise therapy.
2. Description of the Related Art
FIG. 14 is a diagram illustrating the configuration of a conventional exercise therapy device disclosed in Japanese Unexamined Patent Application Publication No. Hei 11-169484. In this figure, a pulley 201 is connected to pedals 202, and a pulley 203 is provided between the pulley 201 and a motor 207. A belt 204 is looped between the pulleys 201 and 203, and a pulley 205 is provided in such a way as to be integrally joined to the pulley 203. A belt 206 is looped between the pulley 205 and a motor 207. Magnets 208 and 209 are mounted on the pulleys 201 and 205, respectively. Hall elements 210 and 211 are disposed so as to cooperate with the magnets 208 and 209, respectively, for generating signals each time they detect a corresponding one of the magnets 208 and 209. A computer 212 receives the signals from the Hall elements 210 and 211, for calculating the rotational speeds of the pulleys 201 and 205. A load control device 213 controls the load on the motor 207 in accordance with the rotational speeds calculated by this computer 212.
Next, an operation of this conventional exercise therapy device is described hereinbelow. The rotation of each of the pedals 202 is transmitted to and accelerated by the pulley 205 looped between the pulleys 201 and 203, and then transmitted to the motor 207 by the belt 206. A pulse is outputted from each of the Hall elements 210 and 211 at each rotation of a corresponding one of the pulleys 201 and 205. Then, after calculating the number of the pulses, the computer 212 outputs the pulses to the load control device 213. The load control device 213 determines the rotational speed of the motor 207 in accordance with the number of the pulses, and controls the load on the motor 207.
Further, when different loads are imposed on the left and right legs, respectively, of an exerciser from the left and right pedals, the conventional exercise therapy device repeats an operation of alternately imposing a high load and a low load on the legs of the exerciser so that a phase angle corresponding to a position at which the high load is imposed on one of the legs differs by xcfx80 from a phase angle corresponding to a position at which the low load is imposed on the other leg. That is, now assuming that the high load is imposed on the right leg at an easiest-to-push position when the right pedal is pushed by the right foot, and that a low load is imposed on the left leg at a position (namely, an easiest-to-push position when the left pedal is pushed by the left foot) corresponding to a phase angle, which is changed by xcfx80 from the phase angle corresponding to the easiest-to-push position for the right foot, the load imposed on the right leg is higher than the load imposed on the left leg. This is effective especially in the case where an exerciser wishes to train the right leg.
With the conventional exercise therapy device as constructed above, when the pedal 202 is positioned within a range of rotation angles other than the top dead center and the bottom dead center, a rotational load on the pedal is not reduced. Therefore, when a cerebrally handicapped person or an aged person, whose muscular strength (of, for instance, femoral quadriceps and coxal extensor group) has declined and whose motor nerves are numb, undergoes exercise therapy in a range of rotation angles other than the top dead center and the bottom dead center of the pedal 202, he cannot continuously perform a pedaling exercise at all rotation angles. Further, when a frictional load is generated in a low speed rotation region, a high load is caused by the pedaling exercise, so that an exerciser cannot continuously perform a pedaling exercise at all rotation angles. Thus, there has been a problem in that a physically handicapped person or an aged person can neither recover an exercise function nor maintain physical strength in a satisfactory manner by using an exercise therapy device, such as an ergonomic bicycle.
Thus, to eliminate the above drawback, Japanese Unexamined Patent Application Publication No. Hei 11-169484 proposed an exercise therapy device enabling a physically handicapped person or an aged person to smoothly and continuously perform a pedaling exercise to recover exercise function and maintain physical strength.
This exercise therapy device is able to turn a pedal shaft pulley and an intermediate pulley by an assist drive mechanism when the rotational speed of the pedal shaft pulley is reduced to a preset speed or less by an assist motor.
Further, when the assist motor rotates at a preset speed only in one direction at all times and the assist motor is rotated only in one direction by a one-way clutch fixed onto the motor shaft of this assist motor in the assist drive mechanism, a pulley rotatably attached to the motor shaft is rotated together with the motor shaft. Conversely, when the assist motor rotates in the other direction, the pulley is idled with respect to the motor shaft. The assist motor is connected to the pulley by a secondary assist pulley provided on the rotation shaft of the intermediate pulley through an assist belt. The assist motor is connected to the pedal shaft pulley by a primary assist pulley provided on the rotation shaft of the intermediate pulley through a primary belt.
With such a configuration, a physically handicapped person or an aged person can continuously perform a pedaling exercise at all angles when the person undergoes an-exercise therapy, to recover his exercise function and maintain his physical strength.
Further, the exercise therapy device has a one-way clutch for releasing transmission of rotation movement from: a load motor to a pedal shaft pulley. The assist motor is rotated by a load reduction drive mechanism so that the load motor is rotated to reduce a load in a low speed rotation region.
Furthermore, Japanese Unexamined Patent Application Publication No. 10-179660 discloses an exercise load adjusting device in which an AC generator is used in an exercise load generating portion. The generator is switched to a side, at which the generator is controlled and used as a DC brushless servo motor control, when a set exercise load is equal to or less than a mechanical loss, and the generator is switched to another side, at which a load control is performed on an output of the generator, when the set exercise. load is equal to or more than the mechanical loss. Although this exercise load adjusting device uses only one generator, this generator is used mainly for adjusting an exercise load. when the exercise load is equal to or less than the mechanical loss, the generator serves only to compensate for the mechanical loss. The generator does not act to positively give an exerciser an exercise assisting force.
Among the aforementioned conventional devices, the exercise therapy device described in Japanese Patent Application No. 9-345619 employs two motors, that is, a load for generating a load motor, and an assist motor for generating an assisting force. Therefore, this exercise therapy device needs two power transmission systems for transmitting power from a corresponding one of the motors to a corresponding one of the pedals. Thus, this conventional. exercise therapy device has drawbacks in that the construction thereof is complicated; the number of parts is large; and it is difficult to reduce the size, weight, and cost thereof.
Further, the conventional exercise therapy device described in Japanese Unexamined Patent Application Publication No. 10-179660 does not positively give an exerciser an exercise assisting force. Thus, this conventional exercise therapy device has a drawback in that it is difficult for an exerciser, who is a physically infirm handicapped or aged person, to smoothly and continuously perform a pedaling exercise without overextending himself when an assisting force is needed, for instance, when the person starts to pedal, or in a low speed rotation mode.
In view of the above, the present invention is intended to eliminate the aforementioned drawbacks of the conventional devices.
Accordingly, an object of the present invention is to provide an exercise therapy device which enables a physically handicapped or aged person to smoothly and continuously perform a pedaling exercise depending upon the level of his physical strength without overextending himself when the person undergoes exercise therapy, to recover the exercised function and maintain physical strength, and which is simple in construction, compact in size and light in weight, and can be manufactured at low cost by using only a single actuator that has a dual function as a load device and an assisting force generating device.
Bearing the foregoing object in mind, according to the present invention, there is provided an exercise therapy device comprising a drive portion adapted to be manually moved by an exerciser, an actuator connected to the drive portion through a power transmission mechanism, and a control unit for causing the actuator to operate as a load device for providing a load to the drive portion and as an assisting device for providing an assisting force to the drive portion when the drive portion is manually moved by the exerciser.
Thus, the exercise therapy device does not require two actuators, that is, a load motor (or generator) for generating a load, and an assisting motor for generating an assisting force, both of which are needed in the conventional devices. A single actuator can serve as both a load motor and an assisting motor. The exercise therapy device of the present invention is effective or advantageous in that the construction of the entire device can be simplified, and that the miniaturization and cost-reduction of the device can be made.
Preferably, the control unit may adjust and limit an assisting force or torque when the actuator is used as an assisting device.
In such a case, the assisting torque is adjusted in accordance with an allowable level for each of individual exercisers. Safety can be assured absolutely or in a manner suitable for each of the individual exercisers by restricting an obviously dangerous force. In the case where the assisting torque is adjusted to a rather low level, the actuator does not operate until an exerciser exerts a certain level of his or her power to move the drive portion. Consequently, the exerciser cannot depend entirely on the assisting force of the actuator. This serves to promote his or her exercise.
Preferably, the control unit may make an assisting force effective, based on a position or a range of rotational angles, at which a mechanical friction of the drive portion is more than a force applied to the drive portion by an exerciser moving the drive portion, or at which the drive portion cannot be driven by physical ability of the exerciser, when the actuator is used as an assisting device.
With such an arrangement, the device compensates for the mechanical friction only in a range in which the exerciser cannot rotate the pedal, instead of the entire range of one revolution of the drive portion, e.g., pedals. Even in the case of an exerciser who cannot continuously perform pedaling because the entire region of rotational angles includes parts, in which the strength of the exerciser (or the greatest force exerted by the exerciser). is less than the magnitude of mechanical friction, and in which degradation in his or her physical strength due to, for instance, hemiplegia, hampers the pedaling by the exerciser, the exercise therapy device of the invention enables him to continuously perform pedaling.
Preferably, when the actuator is used as a load device, the control unit may adjust and limit the speed of the drive portion during an exerciser performs an exercise while moving said drive portion.
In such a case, the exerciser can be prevented from performing pedaling at an excessive speed during his or her exercise. Thus, the exerciser does not pedal at an excessive speed. This prevents him from getting a strain in his leg and getting ill owing to an abrupt and strenuous exercise.
Preferably, when the actuator is used as an assisting device, the control unit may adjust and limit the speed of the drive portion during an exerciser performs an exercise while moving the drive portion.
In such a case, safety can be ensured in absolutely or in a manner suitable for each of the individual exercisers by setting a maximum or limit speed of the drive portion in correlation to a speed at which each exerciser performs an exercise or moves the drive portion, and by preventing the speed of the drive portion from increasing to an obviously dangerous value. Moreover, in the case where the speed generated owing to the assisting torque of the actuator is set in such a manner as to be lower than the pedaling speed to be employed at the exercise, the assisting force can be made to be effective only in a part, in which an exerciser can not perform pedaling because of fatigue or degradation in his strength, of the entire range. Conversely, in a part, in which the exerciser can perform the exercise by himself, he or she may be adapted to perform the exercise by using his or her own strength or force.
Moreover, to obtain a constant pedaling speed during an exercise, a reaction force (or load) from the drive portion or pedals should be balanced against a force applied thereto by an exerciser. However, when the actuator is used as a load device, the control unit may adjust and limit a load torque generated by the actuator to the drive portion during the exerciser performs an exercise while moving the drive portion.
In such a case, as the response of the device is enhanced, the exerciser needs to have higher agility, but he or she is prevented for exerting an obviously dangerous force by restricting the limit of the load torque of the actuator in such a control operation. Consequently, the exerciser can be prevented from being endangered. In addition, safety can be ensured in a manner suitable for each of individual exercisers.
Preferably, the control unit may obtain a load in a rotation stopping mode and a low speed rotation mode of the; actuator by supplying electric current to the actuator in the rotation stopping mode and the low speed rotation mode.
In such a case, in order to allow the actuator to serve as a load, there is no need for the actuator to function as a generator which generates electric power to be wastefully consumed though such wasteful power consumption is necessary in the conventional devices referred to above. Even when generation of sufficient electric power for a target load is unavailable, as in the case of the conventional devices, such a load can be generated by the actuator by supplying current thereto. Thus, an exerciser, such as an aged person, a patient or the like who can perform an exercise only at a low speed owing to his physical ability, can use the inventive exercise therapy device in an effective load control range. In addition, the inventive exercise therapy device makes it possible for healthy persons to exercise in a range of speeds, at which they have not achieved yet.
Preferably, the control unit may obtain a load higher than a rated load by supplying to the actuator a current higher than a rated current.
In such a case, with the conventional systems referred to above, an actuator or generator is required to generate electric energy so as provide a load and hence it is possible to obtain a rated load at most by means of the actuator. In contrast to this, according to the present invention, a higher load can be obtained by using the same actuator. Thus, a compact motor having a lower rated load can be used in the device of the present invention. Consequently, the size of the device can be reduced still more.
Preferably, a detector may be provided for detecting a position or an angle of a movable part of the drive portion which is moved by an exerciser when the exerciser causes a movement of the drive portion, so that the control unit can adjust an amount of a load that is put on the exerciser, based on information on the position or angle detected by the detector.
With this arrangement, as compared with the conventional device in which the load on the drive portion cannot be changed in dependence upon a position or rotational angle thereof within one revolution, the present invention enables a change in the load depending upon the position or rotational angle of the drive portion. Thus, a muscle used for rotating the drive portion (e.g., pedals) varies with the position (or rotational angle) of the drive portion. However, the load can be adjusted according to the muscle to be trained, by changing the load in dependence upon the position or rotational angle of the drive portion. Consequently, the effective training of muscles can be achieved. Additionally, even in the case of exercisers who cannot rotate the pedal in a certain region of rotational angles because of degradation in his or her physical strength due to, for instance, hemiplegia, the device of the present invention enables such exercisers to continuously perform an exercise by setting the load on the drive portion in such a manner that the load is changed from a value corresponding to the region of rotational angles, in which such an exerciser cannot rotate the pedal, to a value corresponding to a region of rotational angles, in which the exerciser can rotate the pedal.
Preferably, the control unit may back up a reference point of the position or rotational angle of the movable part of the drive portion upon interruption of a power supply when the exerciser performs an exercise while moving the drive portion.
With this arrangement, when the load is changed with the rotational angles, a reference point is inevitably established at some angle within one revolution. However, even when the power supply is turned off, the reference point determined the last time can be stored and reused. This eliminates the necessity of setting such a reference point again after the power supply is turned on. Consequently, this saves the trouble of setting an angular reference point each time the power supply is turned on. Additionally, repeatability is ensured by using the reference point established the last time once again.
Preferably, the direction of electric current flowing through the actuator may be reversed by the control unit. Thus, the actuator can be used in both cases of normal rotation and reverse rotation.
With this arrangement, a one-way clutch can be used in a reverse rotation mode. In contrast, with the aforementioned conventional devices, an assisting-force providing operation and a load providing operation are changed from one to the other by using a one-way clutch, and hence it is impossible to use the one-way clutch in the reverse rotation mode because the one-way clutch does not functions in this mode. However, with the device of the present invention, the one-way clutch can be used during a reverse rotating movement, in which muscles used for an exercise are different from those used during a forward rotating movement. Thus, during the reverse rotation, the inventive device makes it possible for an exerciser to train muscles different from those used in the forward rotation.
Preferably, in the case of performing a constant-watt load control operation, as the pedaling speed decreases, the load torque applied from the actuator to the drive portion should be increased. If such control operation is correctly performed, the required load torque increases with reduction in the rotational speed of the drive portion. As a result, the strength or force exerted by an exerciser becomes closer to the limit to the muscle strength thereof. Consequently, it becomes difficult for the exerciser to perform pedaling. However, the control unit may facilitate an exercise by limiting the load torque, which should be increased to a high value in a low speed region, to a low value when load control is performed at a constant watt. In such a case, the present invention is advantageous in that the exerciser easily does an exercise while moving the drive portion, e.g., performing pedaling.
Preferably, the control unit may adjust a load torque, which should be increased to a high value in a low speed region in correspondence with a physical ability of an individual exerciser, while taking into consideration of available physical strength thereof, so that the load torque is limited to a low value when load control is performed at a constant watt.
With this arrangement, differences in limit to the muscle strength among the individual exercisers can be eliminated. The setting of a load for facilitating the pedaling is achieved in correspondence with each of the individual exercisers. Thus, the setting of the load can be performed in such a manner as to be adapted to the level of the muscle strength of each of the individual exercisers. Consequently, the present invention can provide ease of pedaling-operation to various persons from healthy persons to physically infirm persons.
Preferably, the control unit may serve to adjust a speed and a load of the drive portion, and is able to adjust the load of the drive portion so that the speed, at which an exerciser moves the drive portion, is maintained at a predetermined speed even when the exerciser tries to move the drive portion at a speed that is higher than the predetermined speed.
With this arrangement, uniform exercise conditions can be specified by setting the rotational speed of the drive portion (e.g., the pedaling speed) in such a way as to have a constant value during an exercise. Thus, the exerciser is prevented from excessive exercise or motion (e.g., pedaling at an excessive speed). This makes it possible to prevent him or her from getting a strain in his or her leg and getting ill owing to an abrupt and strenuous exercise.
Moreover, to perform the load control operation, the output torque of the actuator should be controlled in such a way as to be changed according to a deviation between a target speed and a current speed. However, in the case where the response of the actuator can be only uniquely determined, the output torque is difficult to control. According to the present invention, however, the control unit may have a load control parameter, adjust and determine the response of the actuator in accordance with the load control parameter.
In this case, the response of the actuator and hence the device can be controlled and determined by this control parameter. Consequently, the response can easily be changed.
Preferably, in the case of an exercise performed by a person, the response is evaluated as the exerciser""s feeling caused by pedaling. According to the present invention, the control unit may set the feeling caused by pedaling, which is the feeling of use of the exercise therapy device when an exerciser performs an exercise, by changing the load control parameter.
In this case, the response can be set in terms of the sensation of a person, instead of simple numerical values, representing the exerciser""s feeling caused by pushing. Therefore, even a person, who cannot understand the meaning of numerical values, can change the setting of the device and can easily adjust the load.
Preferably, the control unit may set the load control parameter at different values in correspondence with individual exercises.
In such a case, the optimal value of the response evaluated as the feeling caused by pedaling, which vary with the physical ability and muscle strength of each exerciser, can be determined in correspondence with each of the individual exercisers. When the response is set at the ease-of-pedaling-operation for healthy persons, it is difficult for a physically infirm person to perform pedaling. Thus, the response can be set in accordance with the physical ability and muscle strength of each exerciser. Consequently, the present invention can provide an exercise therapy device by which even physically infirm persons can. easily perform pedaling.
Preferably, a speed detector may be further provided for detecting a speed of the movable part of the drive portion when the drive portion is moved by an exerciser. in this case, the control unit may have an overspeed protection function for preventing, based on detected-speed information from the speed detector, the movable part from being moved beyond a mechanical limit or an electrical limit.
With this arrangement, the pedaling is prevented from being performed at an excessive speed for the device during an exercise. Consequently, the device can be protected from being damaged due to the excessive speed.
Preferably, a current detector may be provided for detecting a current flowing through the actuator, and the control unit may have an overcurrent protection function of preventing, based on detected-current information from the current detector, an overcurrent that would otherwise cause burning of the control unit.
With this arrangement, an instantaneous overcurrent can be prevented from flowing through the device during an exercise. Consequently, the device can be protected from being damaged owing to the instantaneous overcurrent.
Preferably, a current detector may also be provided for detecting a current flowing through the actuator, and the control unit has an overload protection function of preventing, based on detected-current information from thee current detector, the actuator from burning owing to an excessive amount of heat.
Thus, the temperature of the device can be prevented from rising owing to a continuous overload during an exercise. Consequently, the device can be protected from being damaged owing to the overload.
Preferably, the control unit may set and adjust a feeling of use of the exercise therapy device, i.e., the exerciser""s feeling caused by pedaling, by means of mechanical parameters which include a spring constant, a viscosity coefficient, and an inertia coefficient.
In this case, the response to be evaluated as the exerciser""s feeling caused by pedaling can be determined and controlled by employing a mechanical model. Thus, the response can be evaluated as a parameter for use in a mechanical model. Consequently, the recognition of the physical meaning of the response is facilitated.
Preferably, the control unit may measure an equivalent mechanical parameter of a leg of an individual exerciser as a parameter including a spring constant, a viscosity coefficient, and an inertia coefficient.
In this case, an exerciser can be studied by employing a mechanical model. Further, the physical ability of an exerciser can be analyzed according to the mechanical model. This might enable analysis on the correlation among features of mechanical parameters caused by a disease.